Things you won’t learn from the manual

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When running BEAMnrc and DOSXYZnrc simulations on lyra (or elsewhere), bear in mind the following:

  • When specifying a new linac using BEAMnrc, do not include the following in your component module names:
    • Special (non alphanumeric) characters, like +, -, _, and &.
    • Words that are likely to be already used for variables in the EGS code, like ONE, TWO, THREE and EXIT.
    • Spaces.
  • Use the EXACT boundary crossing algorithm whenever you are using very small (submilimetre) voxels in your DOSXYZnrc phantom. Or, according to Walters et al 2007, use the EXACT boundary-crossing algorithm always.
  • When using the BEAMnrc GUI to design your linac, beware of its “previews”. They do not always accurately represent the geometry you are simulating. (In particular, do not rely on previews when using the GUI to set up MLC models using MLCE or when using the MIRROR component modules with different materials in front and behind the mirror.)
  • When using the SLABS component module in BEAMnrc, be aware that regions outside of RMAX are not modelled at all. (Particles passing beyond RMAX will simply disappear – so set RMAX to a suitably large value.) This may be true for other component modules.
  • Do not recompile dosxyznrc or your BEAM linac model while your simulations are running(!).